Concept:
Citrus fruits are identified by their scientific names.
Step 1: Acid lime.
Acid lime is:
\[
\textit{Citrus aurantifolia}
\]
So,
\[
A\rightarrow III
\]
Step 2: Lemon.
Lemon is:
\[
\textit{Citrus limon}
\]
So,
\[
B\rightarrow IV
\]
Step 3: Mandarin.
Mandarin is:
\[
\textit{Citrus reticulata}
\]
So,
\[
C\rightarrow I
\]
Step 4: Sweet orange.
Sweet orange is:
\[
\textit{Citrus sinensis}
\]
So,
\[
D\rightarrow II
\]
Therefore:
\[
A-III,\ B-IV,\ C-I,\ D-II
\]
\[
\therefore \text{Correct Answer is (C)}
\]